Warning: Long Post Ahead...read fast or hit the back button
C40_Pilot,
I'm still waiting for my Altus date and looking forward to it daily. After eight years in the C-17, I understand you needing a change and oh what a change Hickam has to be. If you're like most of the C-17 guys I know, you probably didn't get to see a lot of Charleston other than Base Ops due to all the TDYs.

I take it you are seeing some nice locations from Hickam, and when you're home...wow, what a place to call home.
My choices were limited to KC-135s & variants after 9/11, so thankfully my "rushing" the C-17 squadrons since 1992 (yes...been trying to get here for 11 years) paid off. I am blessed to have this position and give the credit to God for getting me to KCHS, as there ain't no way I had anything to do with it.
Congrats again on the 737 to Hickam.
Yahtz
Titan5,
The Active Duty AF has an assignment process for all officers including pilots. The folks who works these assignments do so from an "Ivory Palace" at Randolph AFB. The organization they work for is called the Air Force Personnel Center (AFPC).
Here are the basics of how assignments work:
While in USAF pilot training Phase III (T-1, or T-38), you will rank order what assignments you would like from those available to your class. I don't know how the dudes at Corpus (AF students going through T-44 trainging then on to C-130s) do their assignments, but I'm guessing it pretty close to the system in T-1 & T-38s.
It's a merit based system meaning the better you do it pilot training, the higher you move in the picking order. Finish number one in SUPT and you get the first pick of the assignments that are sent to your specific SUPT class. There are some exceptions...ie First Assignment Inst Pilots (FAIPs). FAIPS are selected by the Squadron CC after consulting the Flt CC. Often a student gets FAIPed when they wanted something else. FAIPS are almost always in the top third of their class, who generally (again exceptions here too) have the maturity to teach just after graduating from SUPT.
Each airplane(other than the trainers like T-37, T-38s) have crew positions and various qualifications:
Example in the C-17, you have Co-pilots, First Pilots, Aircraft Commanders (AC), Instructor Pilots, and Evaluator Pilots. You can even be an AC for Airland purposes, but be a Airdrop Co-pilot.
Like C40_Pilot said, it always based on the needs of the AF. Sometimes your desires align with the AF needs and you get something really nice...like the C40 to Hawaii.
As far as the heavy side goes (I'll let the fighter guys tell their story), once you are in a Major Weapon System (MWS), ie C-17, C-5, KC-135....plan to stay there for a while. Going from a airlifter (C-5 & C-17) to a tanker (KC-10, KC-135, E-3, E-8, RC-135) or to a C-130 variant and vice versa is called "Cross Flow" and again an extremely rare occurence. This year I think six tanker pilots flowed to airlift to give you an idea of just how rare.
After three to four years in your first operational assignment, you'll have a few options like going back to SUPT as an IP, or moving to another base that flies the plane you are currently qualified in, I.E. KC-135 at Robins to KC-135 at RAF Mildenhall. Some IPs go out to Altus to teach in their MWS like C40_Pilot did in the C-17.
Hope this helps. Got to run. Send me a PM if you want more info.
Yahtz